Development of a Transparent Scratch Resistant Coating through Direct Oxidation of Al-Coated Glass

Abstract

The authors develop a protective transparent coating of aluminum oxide through direct oxidation of aluminum‐coated glass. Aluminum coatings are deposited on low‐iron glass substrates using a physical deposition method and then oxidized at different temperatures. A uniform nano‐porous structure with grain sizes of approximately 30–80 nm is observed. X‐ray diffraction, TEM images, and EDX analysis indicate the formation of crystalline γ‐Al2O3, Si, and stishovite‐SiO2 as a result of interdiffusion. The samples treated at different temperatures have hardness values ranging from 5 to 9 H, which is within the desirable range for industrial scratch‐resistant coatings. The optical transmission of around 75–85% at visible wavelengths makes the proposed technique useful for the design of protective transparent coatings.